wrassp: Interface to the 'ASSP' Library

A wrapper around Michel Scheffers's 'libassp' (<http://libassp.sourceforge.net/>).
The 'libassp' (Advanced Speech Signal Processor) library aims at providing
functionality for handling speech signal files in most common audio formats
and for performing analyses common in phonetic science/speech science. This
includes the calculation of formants, fundamental frequency, root mean
square, auto correlation, a variety of spectral analyses, zero crossing
rate, filtering etc. This wrapper provides R with a large subset of
'libassp's signal processing functions and provides them to the user in a
(hopefully) user-friendly manner.